As unique documents are created and the desire to back-up information is increased the need effectively to archive data increases. On an individual level, information such as letters, property papers, financial documents, photographs and such are preserved for sentimental, personal, and financial reasons. Federal institutions invest time and money to preserving legislative, executive, judicial documents, as well as birth and death records of the citizens. Historical documents are archived to retain the information stored within them as the documents deteriorate with age and become brittle. The archived copies can provide access to the information in the event the original document is lost or destroyed and can further provide multiple copies for access to numerous individual.
Due to the sheer volume of the above described data, paper-based storage is expensive and very cumbersome. Furthermore, paper is susceptible to environmental hazards such as water and fire. Paper documents do not age well with time unless great care is taken to preserve the paper. As a result, alternative storage techniques such as microfilm/microfiche and electronic memory were developed.
In the microfilm technology, images are preserved similar to the black and white photography process. This process utilizes image reduction techniques to reduce the size of images which are later exposed on to photosensitive films. These films are then preserved in a controlled environment for long-term preservation. However, this technology requires special microfilm viewers to view the images. Furthermore, high-quality hard-copy reproduction is expensive and the duplication process is difficult. In addition to these disadvantages, high-speed storage and retrieval are not possible with microfilm technology.
Another form of archiving is electronic storage. Data are stored electronically in the form of digital bits and using integrated circuits on semiconductor memory. Semiconductor memory can be broadly classified as either volatile and non-volatile. Volatile memory requires electrical power to retain information, while non-volatile memory can retain stored information even when not powered. An example of volatile memory is random access memory (RAM) used in most computers. Non-volatile memory includes semiconductor based flash memory, read-only memory (ROM) and most magnetic storage and optical disc storage such as CD ROMs and DVD ROMs. However, even though the semiconductor memory stores the data in a compact area, the data itself is processed and digitized prior to storage. The information must be converted to digital bits, which are represented in various forms depending on the medium of storage. In semiconductor memory, the digital bits are represented by different voltage levels that are stored using integrated circuits and/or capacitors. On CD ROMs the bits are represented as “pits” and “grounds” that reflect a laser in different ways to read the CD ROM. In most semiconductor memory applications the digital bits are encoded prior to storage, and thus require a decoding technique for retrieving the data. This digitalization of data prior to storage can result in quantization losses. Furthermore, semiconductor memory depends very much on the current mainstream technology, thereby forcing the users to upgrade frequently to new types of storage media and media reading devices.
Therefore, a stable long-term image archiving system capable of storing a large number of images in a compact medium is desired.
Further, an archiving medium that is resistant to fire, water and time deterioration is desired.
Yet further, a high-speed storage and retrieval system for rapid access to images is desired.